With the rapid development of the Internet and the popularization of the mobile phone with the large screen and multiple functions, a large quantity of mobile data multimedia services and various broad bandwidth multimedia services occur, such as the video conference, television broadcast, video on demand, advertisement, online education, and interactive game and so on, which not only satisfies the continuously increased service demand of the mobile user, but also brings new service increasing points for mobile operators at the same time. These mobile data multimedia services need that a plurality of users are able to receive the same data at the same time, and comparing with the common data service, these mobile data multimedia services have features of large data quantity, long duration, and sensitive time delay and so on.
In order to effectively utilize the mobile network resources, the 3rd Generation Partnership Project (3GPP) proposes the Multimedia Broadcast Multicast Service (MBMS), and this service is a technique of transmitting data from one data source to a plurality of destinations, which implements to share the network (including the core network and the access network) resources, and improves the utilization ratio of the network resources (especially the air interface resources). The MBMS defined by the 3GPP is not only able to implement the pure text and low speed message classified multicast and broadcast, but also able to implement the multicast and broadcast of the high speed multimedia service, and provide various rich video, audio and multimedia services, which undoubtedly complies with the trend of the development of the future mobile data, and provides a better service prospect for the development of the LTE.
In the LTE, the MBMS service can adopt a way of the multicast mode, which is called as the Multicast/Broadcast over Single Frequency Network (MBSFN) sending mode, and the MBMS service sent by adopting the multicast mode is also called as the MBSFN service, which is able to adopt the same modulation and coding format in a plurality of cells, and adopt the same physical resources to send the same content, and the features of the MBMS cell transmission are as follows: 1) synchronization transmission in the MBSFN area; 2) the MBMS transmission combination of multiple cells is supported; 3) the Multicast Traffic Channel (MTCH) and the Multicast Control Channel (MCCH) are mapped into the Multicast Channel (MCH) in the point to multipoint (p-T-m) mode; 4) the MBSFN synchronization area, MBSFN area, MBSFN transmission, advertisement, and reserved cell are all maintained in the semi-static configuration by operations. Thus, User Equipment (UE) of a plurality of cells can receive a plurality of MBMS data with the same content and carry out the Single Frequent Network (SFN) combination, thereby being able to improve the gain of the receiving signal. A plurality of cells adopting the same physical resources and sending the same MBMS service in the MBSFN sending mode composes one MBSFN area. In the practical LTE networking, one MBSFN area has a plurality MBSFN services, and all the MBSFN services belonging to one MBSFN area are called as one MBSFN service group, and that is to say one MBSFN service group only belonging to one MBSFN area. One MBSFN area comprises a plurality of cells, and each cell is configured with one completely same MBSFN service group. The data channel MTCH of a plurality of MBSFN services with the same MBSFN area and the control channel MCCH of the MBSFN services can be multiplexed to one Multicast Channel (MCH). The MCCH and a plurality of MTCHs of the same MBSFN area namely a plurality of logic channels can be mapped into the same one transmission channel MCH; the transmission channel MCH is mapped to Physical Multicast Channel (PMCH), and one PMCH occupies part or all of one subframe in the frequency domain, that is to say, one MBSFN subframe can multiplex a plurality of PMCHs by frequency division, and preferably, the whole frequency domain of one MBSFN subframe can only be allocated to one PMCH.
As shown in FIG. 1, in the LTE system, MCH is a transmission channel, which is characterized by the transmission of point to multipoint, and the corresponding physical resources are multicast resources allocated by the system for the transmission of MBMS services (MTCH), and one MCH is borne by some multicast resources which include several MBSFN frames and MBSFN subframes. The configuration of the multicast resources include a wireless frame allocation mode and a wireless subframe allocation model, and taking subframe as a unit, the multicast resources of each MBSFN area can be divided into multiple groups according to certain patterns, and each group or multiple groups can constitute one MCH. The pattern used to constitute each MCH is called MSAP (MBSFN subframe configuration pattern) of the MCH, and a set of MSAP describes the physical resource of one MCH channel. Each cell can have one or more MCHs, and each MCH only corresponds to a set of MSAP and belongs to one MBSFN area uniquely, but each MBSFN area can have one or more MCHs, and the configuration method of multicast resources configured by each MCH is to configure a set of MSAP for each MCH.
As shown in FIG. 2, in order to improve the transmission efficiency of MTCH, multiple MTCHs borne by each MCH can adopt a dynamic scheduling method, which can multiplex two or more than two MTCHs in the same MBSFN subframe and occupy part of resources of the subframe. In the existing public technologies, MSAP occasion is introduced into the concept of MSAP at the same time, which indicates all multicast resources included in one MCH corresponding to a certain MSAP in one period of time. Multiple MTCHs and dynamic scheduling information are sent in one MSAP occasion, also including MCCH, and dynamic scheduling information can be borne in the MAC control element, or borne in a separate logical channel MSCH (Multicast scheduling channel), and the time span of one MSAP occasion is a scheduling period, also known as a dynamic scheduling period. One MCH allocates one or more MBSFN subframes in one or more MBSFN frames through MSAP, wherein subframes sent in multicast mode are called MBSFN subframes, and the frames which contain MBSFN subframes are called MBSFN frames.
In the invention, each MSAP occasion configured by one MCH bears dynamic scheduling information which is referred to as scheduling information for short, carrying mapping information from MTCH to auxiliary MBSFN subframe, and the mapping information relies on the relation of serial number and index of MBSFN subframe in one scheduling period to be determined, and UE can know which MBSFN subframes each MTCH is allocated to by reading the scheduling information, and UE reads its interested MTCH in the corresponding MBSFN subframes but ignores the MBSFN subframes which it is not required to read, therefore improving MBMS service receiving efficiency of UE and saving power consumption of UE. Said MBSFN subframe number is determined as follows: all MBSFN subframe allocated by one MCH in one scheduling period are arranged in order and numbered in sequence. For example, the total number of MBSFN subframes allocated by MCH channel in one period is 100, thus the subframe number is from 0 to 99, or from 1 to 100.
In the existing LTE technology, multiple transmission channels multiplex a MCH channel as follows: one subframe corresponds to one Transmission Time Interval (TTI), and one or more Transport Blocks (TB) can be sent in one TTI, and each TB corresponds to one Media Access Control Protocol Data Unit (MAC PDU). A MAC PDU contains a plurality of Media Access Control Service Data Units (MAC SDU), and these MAC SDUs can be from different logical channels, and in the invention, possible logical channels include MTCH, MCCH, MSCH, etc. The data from different logical channels are concatenated together to be sent in the physical channels. In order to distinguish the MAC SDU from different logical channels, MAC PDU carries the identification information, which includes specifically an identification of logical channel, position information of data block of the logical channel in the MAC PDU and so on, for the receiving end distinguishing data blocks from different logical channels.
For dynamic multiplexing of MBMS services, in one scheduling period, one MTCH or the continuous data transmission of one MBMS service, that is, the data of one service continuously occupies the MBSFN subframe resources of the MCH channel, until service data of the service which needs to be sent in the scheduling period has been transmitted completely. Data of different services can be sent in the same MBSFN subframe. That is, service data from different services can be concatenated together to be sent in the same MAC PDU. The above service sending sequence can be notified to the receiving end through MCCH channel or other signaling.
In the LTE system, transmission channel generates a transmission block which is sent to the physical channel, and the physical channel performs physical channel processing for the transmission block including coding, and the coding mode includes Turbo code or convolutional code, and coding processing also includes puncturing data and interleaving processing, and physical channel processing also includes sending modulated data, which has been processed by coding and so on, to the wireless interface, and the modulation can be QPSK, or 8PSK, or 16QAM, or 32QAM, etc. Different modulation and coding affect the bandwidth and quality of channel, for example, with a relative high coding rate and a relative low redundant data, more service data can be transmitted, but the coding gain is reduced and the channel bit error rate is relatively increased, and for another example, QPSK has a smaller bearing capacity for service data compared with 16QAM, but it has a lower requirement of the channel environment and its channel bit error rate is smaller. The concept of MCS is defined in the LTE system, and the so-called MCS refers to modulation and coding scheme, and a set of MCS includes modulation and coding mode, rate and other parameters.
According to different MBMS service types, different services have different QoS requirements, for example, multimedia real-time service, such as voice and video, requires a lower channel bit error rate to enhance user's experience of receiving and watching, and in general, the channel bit error rate of this kind of service shall be required to be 1%. Text service or download service has a higher requirement for bandwidth but a relative lower requirement for channel bit error rate, and the channel bit error rate of this kind of service is required to be 10%, and MCCH and MSCH have a higher requirement for channel bit error rate, when logical channel messages of this kind of controlling signaling are sent at wireless interface. When the services have different requirements for channel bit error rate and logical channel of control signaling is multiplexing to the same transmission channel and is mapped to the same physical channel, it is a problem to be solved in the LTE system on how to employ different channel modulation and coding schemes for different services to improve utilization efficiency of wireless resources and satisfy transmission requirements of different services and control signaling.